As various pathogenic microbes and substances are being treated in dedicated facilities, such as laboratories, research facilities, hospitals, glove boxes and other special containment areas, and also in equipment for biowaste destruction, it is of increasing importance to ensure that none of these agents escapes outside such facilities or equipment at any time during the various processing stages. Autoclaves are typically used for sterilization of various media, equipment, tools and waste materials.
During use of such equipment or facilities, gases and vapors, typically air and steam, are led both into the facility and out of it. A particular case is the exhaust from an autoclave used for sterilization. During an operational process, the autoclave goes through various cycles of evacuation and repressurization, whereby the risk of still viable hazardous agents escaping through an exhaust channel is obvious, in particular during the early stages of the process when the specified sterilization temperature has not yet been reached. To decrease this risk, filters are often arranged in the exhaust line. An effective way of ensuring that the exhaust stream is sterile is to provide an incinerator in the exhaust line, but open flame incinerators are not easy to operate and not cost-effective, and they pose other risks.
Sterilization in the context of the present discussion includes the killing of microbes including bacteria and viruses so as to render them non-pathogenic, as well as the destruction of other biological agents that may cause harmful effects. Exhaust fluids in this context mean gases which are non-condensable under the normal operational conditions of the device to which the exhaust line is connected, such as atmospheric gases, as well as condensable vapors, and also any particles suspended in these, and which exit a facility or equipment in order to be sterilized in accordance with the invention.
In International patent application WO2008/105696, a device and process for treating an autoclave exhaust stream are disclosed. The invention disclosed in WO2008/105696 is based on the arrangement of two filters in series in the exhaust line, and a heater between the filters for evaporating condensate that tends to form in the line. With the use of the heater, the condensate can be driven through a hydrophobic filter which will not allow liquid water through, and the condensate can also be heated to sterilization temperature.
In international patent application WO 98/16263 are disclosed a method and apparatus for sterilizing air to be used for e.g. pneumatic medical instruments, cleanrooms and aircraft cabins. The device comprises a replaceable filter.